HR: 1330h
AN: S42E-0220    [PDF]
TI: Effects of Crustal Layering on Source Parameter Inversion from Coseismic Displacement Data
AU: * Amoruso, A
EM: antonella.amoruso@aquila.infn.it
AF: Dipartimento di Fisica - Universita' dell'Aquila, Via Vetoio 10, Coppito (AQ), 67010 Italy
AU: Crescentini, L
EM: luca.crescentini@unicam.it
AF: Dipartimento di Scienze della Terra - Universita' di Camerino, Via Gentile III da Varano, Camerino (MC), 62032 Italy
AU: Fidani, C
EM: cristiano.fidani@lngs.infn.it
AF: Consorzio di Ricerca del Gran Sasso, SS 17/bis - km 18+910, Assergi (AQ), 67010 Italy
AB: Usually source parameters are obtained by the inversion of coseismic displacements assuming a homogeneous half-space. Under this assumption, coseismic surface displacements for an assigned source depend on the ratio between the Lam\`e parameters $\mu$ and $\lambda$. Since rocks often behave like a Poisson solid, actual values of the elastic moduli do not affect the results. When crustal layering is taken into account, coseismic displacements depend on the values of the elastic moduli in all the layers, even if the ratio $\mu$/$\lambda$ is constant. Inversion of coseismic data assuming a layered medium is however impractical, because resolution of the inverse problem requires solving many direct problems. We have studied the effects of layering on inversions of coseismic displacements for finite dip-slip faults by computing surface displacements with different 3-D analytic codes and inverting them using a nonlinear inversion algorithm based on the homogeneous half-space assumption. Some source parameters (mainly fault dip, width and depth) noticeably depart from their "real" values.
DE: 7215 Earthquake parameters
DE: 7260 Theory and modeling
SC: Seismology [S]
MN: 2003 Fall Meeting